Genetic drift is an evolutive force that affects small populations and changes their allelic and genotypic frequencies by randomly fixating some alleles and eliminating others. Option A) Genetic Drift.
Genetic drift is an evolutionary mechanism in which the allelic frequencies in a population change through many generations. Its effects are harder in a small-sized population.
Genetic drift results in some alleles loss, even those that are beneficial for the population, and the fixation of some other alleles by an increase in their frequencies. The final consequence is to randomly attach one of the alleles.
Two events that involve genetic drift are the bottleneck effect and the founder effect.
Now we need to define which option is the best.
What happened?
Gene flow
This is not the case, because gene flow decreases heterogeneity between populations, reducing genetic variation. Besides if these populations are far away, gene flow would be difficult.
Nonrandom matings
This is not the case, because with nonrandom mating there would not be such a change in frequencies.
Directional selection
Directional selection does not seem to be the cause either, because both populations are under the exact same environmental conditions, so pressures acting on them are the same. There is no change in this aspect.
Genetic Drift
I believe this is the best option. Genetic drift causes a change in allele frequencies and affects small populations. These populations might have been separated for a long time, and suffered the effects of genetic drift. It might be a founder effect case, with the smaller population being the newest one.
The correct option is Genetic Drift. Option A.
You can learn more about genetic drift at
https://brainly.com/question/9572014
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Complete question
One population of a species has 25 individuals, all with genotype AA; a second population of this species has 40 individuals, all with genotype aa.
Assume that these populations live far apart but in similar environmental conditions.
Based on this information, the observed genetic variation most likely resulted from.
(A) genetic drift.
(B) gene flow
(C) nonrandom mating.
(D) directional selection.
